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Xu W, Langhans SA, Johnson DK, Stauff E, Kandula VVR, Kecskemethy HH, Averill LW, Yue X. Radiotracers for Molecular Imaging of Angiotensin-Converting Enzyme 2. Int J Mol Sci 2024; 25:9419. [PMID: 39273366 PMCID: PMC11395405 DOI: 10.3390/ijms25179419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Revised: 08/23/2024] [Accepted: 08/24/2024] [Indexed: 09/15/2024] Open
Abstract
Angiotensin-converting enzymes (ACE) are well-known for their roles in both blood pressure regulation via the renin-angiotensin system as well as functions in fertility, immunity, hematopoiesis, and many others. The two main isoforms of ACE include ACE and ACE-2 (ACE2). Both isoforms have similar structures and mediate numerous effects on the cardiovascular system. Most remarkably, ACE2 serves as an entry receptor for SARS-CoV-2. Understanding the interaction between the virus and ACE2 is vital to combating the disease and preventing a similar pandemic in the future. Noninvasive imaging techniques such as positron emission tomography and single photon emission computed tomography could noninvasively and quantitatively assess in vivo ACE2 expression levels. ACE2-targeted imaging can be used as a valuable tool to better understand the mechanism of the infection process and the potential roles of ACE2 in homeostasis and related diseases. Together, this information can aid in the identification of potential therapeutic drugs for infectious diseases, cancer, and many ACE2-related diseases. The present review summarized the state-of-the-art radiotracers for ACE2 imaging, including their chemical design, pharmacological properties, radiochemistry, as well as preclinical and human molecular imaging findings. We also discussed the advantages and limitations of the currently developed ACE2-specific radiotracers.
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Affiliation(s)
- Wenqi Xu
- Department of Radiology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
- Diagnostic & Research PET/MR Center, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
| | - Sigrid A Langhans
- Diagnostic & Research PET/MR Center, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
- Division of Neurology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
| | - David K Johnson
- Computational Chemical Biology Core, Molecular Graphics and Modeling Laboratory, University of Kansas, Lawrence, KS 66047, USA
| | - Erik Stauff
- Department of Radiology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
- Diagnostic & Research PET/MR Center, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
| | - Vinay V R Kandula
- Department of Radiology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
| | - Heidi H Kecskemethy
- Department of Radiology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
- Diagnostic & Research PET/MR Center, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
| | - Lauren W Averill
- Department of Radiology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
- Diagnostic & Research PET/MR Center, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
| | - Xuyi Yue
- Department of Radiology, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
- Diagnostic & Research PET/MR Center, Nemours Children's Health, Delaware, Wilmington, DE 19803, USA
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Pijeira MSO, Nunes PSG, Chaviano SL, Diaz AMA, DaSilva JN, Ricci-Junior E, Alencar LMR, Chen X, Santos-Oliveira R. Medicinal (Radio) Chemistry: Building Radiopharmaceuticals for the Future. Curr Med Chem 2024; 31:5481-5534. [PMID: 37594105 DOI: 10.2174/0929867331666230818092634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/30/2023] [Accepted: 07/13/2023] [Indexed: 08/19/2023]
Abstract
Radiopharmaceuticals are increasingly playing a leading role in diagnosing, monitoring, and treating disease. In comparison with conventional pharmaceuticals, the development of radiopharmaceuticals does follow the principles of medicinal chemistry in the context of imaging-altered physiological processes. The design of a novel radiopharmaceutical has several steps similar to conventional drug discovery and some particularity. In the present work, we revisited the insights of medicinal chemistry in the current radiopharmaceutical development giving examples in oncology, neurology, and cardiology. In this regard, we overviewed the literature on radiopharmaceutical development to study overexpressed targets such as prostate-specific membrane antigen and fibroblast activation protein in cancer; β-amyloid plaques and tau protein in brain disorders; and angiotensin II type 1 receptor in cardiac disease. The work addresses concepts in the field of radiopharmacy with a special focus on the potential use of radiopharmaceuticals for nuclear imaging and theranostics.
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Affiliation(s)
- Martha Sahylí Ortega Pijeira
- Laboratory of Nanoradiopharmaceuticals and Synthesis of Novel Radiopharmaceuticals, Brazilian Nuclear Energy Commission, Nuclear Engineering Institute, Rio de Janeiro 21941906, Brazil
| | - Paulo Sérgio Gonçalves Nunes
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas SP13083-970, Brazil
| | - Samila Leon Chaviano
- Laboratoire de Biomatériaux pour l'Imagerie Médicale, Axe Médicine Régénératrice, Centre de Recherche du Centre Hospitalier Universitaire de Québec - Université Laval, Québec, QC, Canada
| | - Aida M Abreu Diaz
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
- Institute de Génie Biomédical, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Jean N DaSilva
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
- Institute de Génie Biomédical, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Eduardo Ricci-Junior
- Laboratório de Desenvolvimento Galênico, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil
| | - Luciana Magalhães Rebelo Alencar
- Laboratory of Biophysics and Nanosystems, Federal University of Maranhão, Av. dos Portugueses, 1966, Vila Bacanga, São Luís MA65080-805, Brazil
| | - Xiaoyuan Chen
- Departments of Diagnostic Radiology, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and Faculty of Engineering, National University of Singapore 117597, Singapore
- Clinical Imaging Research Centre, Centre for Translational Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 117599, Singapore
- Nanomedicine Translational Research Program, NUS Center for Nanomedicine, Yong Loo Lin School of Medicine, National University of Singapore 117597, Singapore
| | - Ralph Santos-Oliveira
- Laboratory of Nanoradiopharmaceuticals and Synthesis of Novel Radiopharmaceuticals, Brazilian Nuclear Energy Commission, Nuclear Engineering Institute, Rio de Janeiro 21941906, Brazil
- Laboratory of Radiopharmacy and Nanoradiopharmaceuticals, Rio de Janeiro State University, Rio de Janeiro 23070200, Brazil
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Abreu Diaz AM, Rodriguez Riera Z, Lee Y, Esteves LM, Normandeau CO, Fezas B, Hernandez Saiz A, Tournoux F, Juneau D, DaSilva JN. [ 18 F]Fluoropyridine-losartan: A new approach toward human Positron Emission Tomography imaging of Angiotensin II Type 1 receptors. J Labelled Comp Radiopharm 2023; 66:73-85. [PMID: 36656923 DOI: 10.1002/jlcr.4014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/27/2022] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
Angiotensin II type 1 receptors (AT1 R) blocker losartan is used in patients with renal and cardiovascular diseases. [18 F]fluoropyridine-losartan has shown favorable binding profile for quantitative renal PET imaging of AT1 R with selective binding in rats and pigs, low interference of radiometabolites and appropriate dosimetry for clinical translation. A new approach was developed to produce [18 F]fluoropyridine-losartan in very high molar activity. Automated radiosynthesis was performed in a three-step, two-pot, and two-HPLC-purification procedure within 2 h. Pure [18 F]FPyKYNE was obtained by radiofluorination of NO2 PyKYNE and silica-gel-HPLC purification (40 ± 9%), preventing the formation of nitropyridine-losartan in the second step. Conjugation with trityl-losartan azide via click chemistry, followed by acid hydrolysis, C18-HPLC purification and reformulation provided [18 F]fluoropyridine-losartan in 11 ± 2% (decay-corrected from [18 F]fluoride, EOB). Using tris[(1-(3-hydroxypropyl)-1H-1,2,3-triazol-4-yl)methyl]-amine (THPTA) as a Cu(I)-stabilizing agent for coupling [18 F]FPyKYNE to the unprotected losartan azide afforded [18 F]fluoropyridine-losartan in similar yields (11 ± 3%, decay-corrected from [18 F]fluoride, EOB). Reverse-phase HPLC was optimized by reducing the pH of the mobile phase to achieve complete purification and high molar activities (467 ± 60 GBq/μmol). The use of radioprotectants prevented tracer radiolysis for 10 h (RCP > 99%). The product passed the quality control testing. This reproducible automated radiosynthesis process will allow in vivo PET imaging of AT1 R expression in several diseases.
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Affiliation(s)
- Aida Mary Abreu Diaz
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de pharmacologie et physiologie, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Institut de génie biomédical, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Departamento de Radioquímica, Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de la Habana, La Habana, Cuba
| | - Zalua Rodriguez Riera
- Departamento de Radioquímica, Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de la Habana, La Habana, Cuba
| | - Yanick Lee
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Institut de génie biomédical, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
| | - Luis Miguel Esteves
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- CRCHUM site, Isologic Innovative Radiopharmaceuticals, Lachine, Québec, Canada
| | | | - Baptiste Fezas
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
| | | | - François Tournoux
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Centre cardiovasculaire, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Daniel Juneau
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Médecine nucléaire, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Département de radiologie, radio-oncologie et médecine nucléaire, Faculté de médecine, Université de Montréal, Pavillon Roger-Gaudry, Montréal, Québec, Canada
| | - Jean N DaSilva
- Laboratoire de Radiochimie et Cyclotron, Centre de Recherche du CHUM, Montréal, Québec, Canada
- Département de pharmacologie et physiologie, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Institut de génie biomédical, Faculté de médecine, Université de Montréal, Pavillon Paul-G. Desmarais, Montréal, Québec, Canada
- Département de radiologie, radio-oncologie et médecine nucléaire, Faculté de médecine, Université de Montréal, Pavillon Roger-Gaudry, Montréal, Québec, Canada
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Synthesis and Evaluation of [ 18F]FEtLos and [ 18F]AMBF 3Los as Novel 18F-Labelled Losartan Derivatives for Molecular Imaging of Angiotensin II Type 1 Receptors. Molecules 2020; 25:molecules25081872. [PMID: 32325695 PMCID: PMC7221519 DOI: 10.3390/molecules25081872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/18/2020] [Accepted: 01/23/2020] [Indexed: 01/13/2023] Open
Abstract
Losartan is widely used in clinics to treat cardiovascular related diseases by selectively blocking the angiotensin II type 1 receptors (AT1Rs), which regulate the renin-angiotensin system (RAS). Therefore, monitoring the physiological and pathological biodistribution of AT1R using positron emission tomography (PET) might be a valuable tool to assess the functionality of RAS. Herein, we describe the synthesis and characterization of two novel losartan derivatives PET tracers, [18F]fluoroethyl-losartan ([18F]FEtLos) and [18F]ammoniomethyltrifluoroborate-losartan ([18F]AMBF3Los). [18F]FEtLos was radiolabeled by 18F-fluoroalkylation of losartan potassium using the prosthetic group 2-[18F]fluoroethyl tosylate; whereas [18F]AMBF3Los was prepared following an one-step 18F-19F isotopic exchange reaction, in an overall yield of 2.7 ± 0.9% and 11 ± 4%, respectively, with high radiochemical purity (>95%). Binding competition assays in AT1R-expressing membranes showed that AMBF3Los presented an almost equivalent binding affinity (Ki 7.9 nM) as the cold reference Losartan (Ki 1.5 nM), unlike FEtLos (Ki 2000 nM). In vitro and in vivo assays showed that [18F]AMBF3Los displayed a good binding affinity for AT1R-overexpressing CHO cells and was able to specifically bind to renal AT1R. Hence, our data demonstrate [18F]AMBF3Los as a new tool for PET imaging of AT1R with possible applications for the diagnosis of cardiovascular, inflammatory and cancer diseases.
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Hoffmann M, Chen X, Hirano M, Arimitsu K, Kimura H, Higuchi T, Decker M. 18
F‐Labeled Derivatives of Irbesartan for Angiotensin II Receptor PET Imaging. ChemMedChem 2018; 13:2546-2557. [DOI: 10.1002/cmdc.201800638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Matthias Hoffmann
- Pharmaceutical and Medicinal ChemistryInstitute of Pharmacy and Food ChemistryJulius Maximilian University Würzburg Am Hubland 97074 Würzburg Germany
| | - Xinyu Chen
- Department of Nuclear Medicine and Comprehensive Heart Failure Centre (CHFC)University Hospital of Würzburg Oberdürrbacherstr. 6 97080 Würzburg Germany
| | - Mitsuru Hirano
- Department of Bio-Medical ImagingNational Cerebral and Cardiovascular Centre, 5–7-1 Fujishiro-dai Suita Osaka 565-8565 Japan
| | - Kenji Arimitsu
- Department of Analytical and Bioinorganic ChemistryKyoto Pharmaceutical University 5 Nakauchi-Cho, Misasagi Yamashina-ku Kyoto 607–8414 Japan
| | - Hiroyuki Kimura
- Department of Analytical and Bioinorganic ChemistryKyoto Pharmaceutical University 5 Nakauchi-Cho, Misasagi Yamashina-ku Kyoto 607–8414 Japan
| | - Takahiro Higuchi
- Department of Nuclear Medicine and Comprehensive Heart Failure Centre (CHFC)University Hospital of Würzburg Oberdürrbacherstr. 6 97080 Würzburg Germany
- Department of Bio-Medical ImagingNational Cerebral and Cardiovascular Centre, 5–7-1 Fujishiro-dai Suita Osaka 565-8565 Japan
| | - Michael Decker
- Pharmaceutical and Medicinal ChemistryInstitute of Pharmacy and Food ChemistryJulius Maximilian University Würzburg Am Hubland 97074 Würzburg Germany
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Chen X, Hirano M, Werner RA, Decker M, Higuchi T. Novel 18F-Labeled PET Imaging Agent FV45 Targeting the Renin-Angiotensin System. ACS OMEGA 2018; 3:10460-10470. [PMID: 30288456 PMCID: PMC6166228 DOI: 10.1021/acsomega.8b01885] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 08/14/2018] [Indexed: 06/08/2023]
Abstract
Renin-angiotensin system (RAS) plays an important role in the regulation of blood pressure and hormonal balance. Using positron emission tomography (PET) technology, it is possible to monitor the physiological and pathological distribution of angiotensin II type 1 receptors (AT1), which reflects the functionality of RAS. A new 18F-labeled PET tracer derived from the clinically used AT1 antagonist valsartan showing the least possible chemical alteration from the valsartan structure has been designed and synthesized with several strategies, which can be applied for the syntheses of further derivatives. Radioligand binding study showed that the cold reference FV45 (K i 14.6 nM) has almost equivalent binding affinity as its lead valsartan (K i 11.8 nM) and angiotensin II (K i 1.7 nM). Successful radiolabeling of FV45 in a one-pot radiofluorination followed by the deprotection procedure with 21.8 ± 8.5% radiochemical yield and >99% radiochemical purity (n = 5) enabled a distribution study in rats and opened a path to straightforward large-scale production. A fast and clear kidney uptake could be observed, and this renal uptake could be selectively blocked by pretreatment with AT1-selective antagonist valsartan. Overall, as the first 18F-labeled PET tracer based on a derivation from clinically used drug valsartan with almost identical chemical structure, [18F]FV45 will be a new tool for assessing the RAS function by visualizing AT1 receptor distributions and providing further information regarding cardiovascular system malfunction as well as possible applications in inflammation research and cancer diagnosis.
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Affiliation(s)
- Xinyu Chen
- Department
of Nuclear Medicine, Comprehensive Heart Failure Center, University
Hospital of Würzburg, Würzburg 97080, Germany
| | - Mitsuru Hirano
- Department
of Bio-Medical Imaging, National Cerebral
and Cardiovascular Center, Osaka 565-0873, Japan
| | - Rudolf A. Werner
- Department
of Nuclear Medicine, Comprehensive Heart Failure Center, University
Hospital of Würzburg, Würzburg 97080, Germany
- The
Russell H. Morgan Department of Radiology and Radiological Science,
Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Michael Decker
- Institute of Pharmacy and Food Chemistry, University of Würzburg, Würzburg 97074, Germany
| | - Takahiro Higuchi
- Department
of Nuclear Medicine, Comprehensive Heart Failure Center, University
Hospital of Würzburg, Würzburg 97080, Germany
- Department
of Bio-Medical Imaging, National Cerebral
and Cardiovascular Center, Osaka 565-0873, Japan
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Molecular imaging of cardiac remodelling after myocardial infarction. Basic Res Cardiol 2018; 113:10. [PMID: 29344827 PMCID: PMC5772148 DOI: 10.1007/s00395-018-0668-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 11/17/2017] [Accepted: 01/08/2018] [Indexed: 02/06/2023]
Abstract
Myocardial infarction and subsequent heart failure is a major health burden associated with significant mortality and morbidity in western societies. The ability of cardiac tissue to recover after myocardial infarction is affected by numerous complex cellular and molecular pathways. Unbalance or failure of these pathways can lead to adverse remodelling of the heart and poor prognosis. Current clinical cardiac imaging modalities assess anatomy, perfusion, function, and viability of the myocardium, yet do not offer any insight into the specific molecular pathways involved in the repair process. Novel imaging techniques allow visualisation of these molecular processes and may have significant diagnostic and prognostic values, which could aid clinical management. Single photon-emission tomography, positron-emission tomography, and magnetic resonance imaging are used to visualise various aspects of these molecular processes. Imaging probes are usually attached to radioisotopes or paramagnetic nanoparticles to specifically target biological processes such as: apoptosis, necrosis, inflammation, angiogenesis, and scar formation. Although the results from preclinical studies are promising, translating this work to a clinical environment in a valuable and cost-effective way is extremely challenging. Extensive evaluation evidence of diagnostic and prognostic values in multi-centre clinical trials is still required.
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Shirani J, Singh A, Agrawal S, Dilsizian V. Cardiac molecular imaging to track left ventricular remodeling in heart failure. J Nucl Cardiol 2017; 24:574-590. [PMID: 27480973 DOI: 10.1007/s12350-016-0620-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 07/13/2016] [Indexed: 12/11/2022]
Abstract
Cardiac left ventricular (LV) remodeling is the final common pathway of most primary cardiovascular diseases that manifest clinically as heart failure (HF). The more advanced the systolic HF and LV dysfunction, the worse the prognosis. The knowledge of the molecular, cellular, and neurohormonal mechanisms that lead to myocardial dysfunction and symptomatic HF has expanded rapidly and has allowed sophisticated approaches to understanding and management of the disease. New therapeutic targets for pharmacologic intervention in HF have also been identified through discovery of novel cellular and molecular components of membrane-bound receptor-mediated intracellular signal transduction cascades. Despite all advances, however, the prognosis of systolic HF has remained poor in general. This is, at least in part, related to the (1) relatively late institution of treatment due to reliance on gross functional and structural abnormalities that define the "heart failure phenotype" clinically; (2) remarkable genetic-based interindividual variations in the contribution of each of the many molecular components of cardiac remodeling; and (3) inability to monitor the activity of individual pathways to cardiac remodeling in order to estimate the potential benefits of pharmacologic agents, monitor the need for dose titration, and minimize side effects. Imaging of the recognized ultrastructural components of cardiac remodeling can allow redefinition of heart failure based on its "molecular phenotype," and provide a guide to implementation of "personalized" and "evidence-based" evaluation, treatment, and longitudinal monitoring of the disease beyond what is currently available through randomized controlled clinical trials.
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Affiliation(s)
- Jamshid Shirani
- Department of Cardiology, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, USA.
| | - Amitoj Singh
- Department of Cardiology, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, USA
| | - Sahil Agrawal
- Department of Cardiology, St. Luke's University Health Network, 801 Ostrum Street, Bethlehem, PA, USA
| | - Vasken Dilsizian
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Chen X, Werner RA, Javadi MS, Maya Y, Decker M, Lapa C, Herrmann K, Higuchi T. Radionuclide imaging of neurohormonal system of the heart. Am J Cancer Res 2015; 5:545-58. [PMID: 25825596 PMCID: PMC4377725 DOI: 10.7150/thno.10900] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/02/2015] [Indexed: 12/18/2022] Open
Abstract
Heart failure is one of the growing causes of death especially in developed countries due to longer life expectancy. Although many pharmacological and instrumental therapeutic approaches have been introduced for prevention and treatment of heart failure, there are still limitations and challenges. Nuclear cardiology has experienced rapid growth in the last few decades, in particular the application of single photon emission computed tomography (SPECT) and positron emission tomography (PET), which allow non-invasive functional assessment of cardiac condition including neurohormonal systems involved in heart failure; its application has dramatically improved the capacity for fundamental research and clinical diagnosis. In this article, we review the current status of applying radionuclide technology in non-invasive imaging of neurohormonal system in the heart, especially focusing on the tracers that are currently available. A short discussion about disadvantages and perspectives is also included.
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Abstract
Angiotensin II (AII), an octapeptide member of the renin-angiotensin system (RAS), is formed by the enzyme angiotensin converting enzyme (ACE) and exerts adverse cellular effects through an interaction with its type 1 receptor (AT1R). Both ACE inhibitors and angiotensin receptor blockers (ARB) mitigate the vasoconstrictive, proliferative, proinflammatory, proapoptotic, and profibrotic effects of AII and are widely used as effective anti-remodeling agents in clinical practice. Prediction of individual response to these agents, however, remains problematic and is influenced by many factors including race, gender, and genotype. In addition, systemic and tissue RAS activity do not correlate closely. This report summarizes the results of on-going attempts to noninvasively determine tissue ACE activity and AT1R expression using novel nuclear tracers. It is hoped that the availability of such imaging techniques improve treatment of heart failure through more selective pharmacologic intervention and better dose titration of available drugs.
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Arksey N, Hadizad T, Ismail B, Hachem M, Valdivia AC, Beanlands RS, deKemp RA, DaSilva JN. Synthesis and evaluation of the novel 2-[18F]fluoro-3-propoxy-triazole-pyridine-substituted losartan for imaging AT1 receptors. Bioorg Med Chem 2014; 22:3931-7. [DOI: 10.1016/j.bmc.2014.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/28/2014] [Accepted: 06/06/2014] [Indexed: 11/26/2022]
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Lautamäki R, Knuuti J, Saraste A. Recent Developments in Imaging of Myocardial Angiotensin Receptors. CURRENT CARDIOVASCULAR IMAGING REPORTS 2013. [DOI: 10.1007/s12410-013-9245-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Modeling of the renal kinetics of the AT1 receptor specific PET radioligand [11C]KR31173. BIOMED RESEARCH INTERNATIONAL 2013; 2013:835859. [PMID: 24083243 PMCID: PMC3780470 DOI: 10.1155/2013/835859] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022]
Abstract
Purpose. The radioligand [11C]KR31173 has been introduced for PET imaging of the angiotensin II subtype 1 receptor (AT1R). The purpose of the present project was to employ and validate a compartmental model for quantification of the kinetics of this radioligand in a porcine model of renal ischemia followed by reperfusion (IR). Procedures. Ten domestic pigs were included in the study: five controls and five experimental animals with IR of the left kidney. To achieve IR, acute ischemia was created with a balloon inserted into the left renal artery and inflated for 60 minutes. Reperfusion was achieved by deflation and removal of the balloon. Blood chemistries, urine specific gravity and PH values, and circulating hormones of the renin angiotensin system were measured and PET imaging was performed one week after IR. Cortical time-activity curves obtained from a 90 min [11C]KR31173 dynamic PET study were processed with a compartmental model that included two tissue compartments connected in parallel. Radioligand binding quantified by radioligand retention (80 min value to maximum value ratio) was compared to the binding parameters derived from the compartmental model. A binding ratio was calculated as DVR = DVS/DVNS, where DVS and DVNS represented the distribution volumes of specific binding and nonspecific binding. Receptor binding was also determined by autoradiography in vitro. Results. Correlations between rate constants and binding parameters derived by the convolution and deconvolution curve fittings were significant (r > 0.9). Also significant was the correlation between the retention parameter derived from the tissue activity curve (Yret) and the retention parameter derived from the impulse response function (fret). Furthermore, significant correlations were found between these two retention parameters and DVR. Measurements with PET showed no significant changes in the radioligand binding parameters caused by IR, and these in vivo findings were confirmed by autoradiography performed in vitro. Conclusions. Correlations between various binding parameters support the concept of the parallel connectivity compartmental model. If an arterial input function cannot be obtained, simple radioligand retention may be adequate for estimation of in vivo radioligand binding.
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Analysis of [11C]methyl-candesartan kinetics in the rat kidney for the assessment of angiotensin II type 1 receptor density in vivo with PET. Nucl Med Biol 2013; 40:252-61. [DOI: 10.1016/j.nucmedbio.2012.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 10/30/2012] [Accepted: 10/31/2012] [Indexed: 11/22/2022]
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15
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Fukushima K, Bravo PE, Higuchi T, Schuleri KH, Lin X, Abraham MR, Xia J, Mathews WB, Dannals RF, Lardo AC, Szabo Z, Bengel FM. Molecular hybrid positron emission tomography/computed tomography imaging of cardiac angiotensin II type 1 receptors. J Am Coll Cardiol 2012; 60:2527-34. [PMID: 23158533 DOI: 10.1016/j.jacc.2012.09.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 09/05/2012] [Accepted: 09/25/2012] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The goal of this study was to explore the feasibility of targeted imaging of the angiotensin II type 1 receptor (AT1R) in cardiac tissue, using clinical hybrid positron emission tomography/computed tomography (PET/CT). BACKGROUND AT1R is an attractive imaging target due to its key role in various cardiac pathologies, including post-infarct left ventricular remodeling. METHODS Using the novel AT1R ligand [(11)C]-KR31173, dynamic PET/CT was performed in young farm pigs under healthy conditions (n = 4) and 3 to 4 weeks after experimental myocardial infarction (n = 5). Ex vivo validation was carried out by immunohistochemistry and polymerase chain reaction. First-in-man application was performed in 4 healthy volunteers at baseline and under AT1R blocking. RESULTS In healthy pigs, myocardial KR31173 retention was detectable, regionally homogeneous, and specific for AT1R, as confirmed by blocking experiments. Metabolism in plasma was low (85 ± 2% of intact tracer after 60 min). After myocardial infarction, KR31173 retention, corrected for regional perfusion, revealed AT1R up-regulation in the infarct area relative to remote myocardium, whereas retention was elevated in both regions when compared with myocardium of healthy controls (8.7 ± 0.8% and 7.1 ± 0.3%/min vs. 5.8 ± 0.4%/min for infarct and remote, respectively, vs. healthy controls; p < 0.01 each). Postmortem analysis confirmed AT1R up-regulation in remote and infarct tissue. First-in-man application was safe, and showed detectable and specific myocardial KR31173 retention, albeit at a lower level than pigs (left ventricular average retention: 1.2 ± 0.1%/min vs. 4.4 ± 1.2%/min for humans vs. pigs; p = 0.04). CONCLUSIONS Noninvasive imaging of cardiac AT1R expression is feasible using clinical PET/CT technology. Results provide a rationale for broader clinical testing of AT1R-targeted molecular imaging.
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Affiliation(s)
- Kenji Fukushima
- Division of Nuclear Medicine, Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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Hadizad T, Collins J, E. Antoun R, S. Beanlands R, N. DaSilva J. [11C]Methyl-losartan as a potential ligand for PET imaging angiotensin II AT1 receptors. J Labelled Comp Radiopharm 2011. [DOI: 10.1002/jlcr.1917] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tayebeh Hadizad
- Cardiac PET Centre; University of Ottawa Heart Institute; Ottawa; Ontario; Canada
| | - Jeffrey Collins
- Cardiac PET Centre; University of Ottawa Heart Institute; Ottawa; Ontario; Canada
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17
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Higuchi T, Fukushima K, Xia J, Mathews WB, Lautamäki R, Bravo PE, Javadi MS, Dannals RF, Szabo Z, Bengel FM. Radionuclide Imaging of Angiotensin II Type 1 Receptor Upregulation After Myocardial Ischemia–Reperfusion Injury. J Nucl Med 2010; 51:1956-61. [DOI: 10.2967/jnumed.110.079855] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Åberg O, Lindhe Ö, Hall H, Hellman P, Kihlberg T, Långström B. Synthesis and biological evaluation of [carboxyl-11C]eprosartan. J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1598] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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19
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Eberle AN, Mild G. Receptor-mediated tumor targeting with radiopeptides. J Recept Signal Transduct Res 2009; 29:1-37. [DOI: 10.1080/10799890902732823] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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20
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Szabo Z, Xia J, Mathews WB. Radiopharmaceuticals for renal positron emission tomography imaging. Semin Nucl Med 2008; 38:20-31. [PMID: 18096461 DOI: 10.1053/j.semnuclmed.2007.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Radiopharmaceuticals for functional renal imaging, including renal blood flow, renal blood volume, glomerular excretion, and metabolism have been available for some time. This review outlines radiopharmaceuticals for functional renal imaging as well as those that target pertinent molecular constituents of renal injury and repair. The angiotensin and endothelin receptors are particularly appealing molecular targets for renal imaging because of their association with renal physiology and pathology. Other targets such as the vascular endothelial growth factor (VEGF) receptor, integrin, or phosphatidylserine have been investigated at length for cancer imaging, but they are just as important constituents of the renal injury/repair process. Various diseases can involve identical mechanisms, such as angiogenesis and apoptosis, and radiopharmaceuticals developed for these processes in other organs can also be used for renal imaging. The sensitivity and spatial resolution of positron emission tomography makes it an ideal tool for molecular and functional kidney imaging. Radiopharmaceutical development for the kidneys must focus on achieving high target selectivity and binding affinity, stability and slow metabolism in vivo, and minimal nonspecific accumulation and urinary excretion.
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Affiliation(s)
- Zsolt Szabo
- Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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21
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Xia J, Seckin E, Xiang Y, Vranesic M, Mathews WB, Hong K, Bluemke DA, Lerman LO, Szabo Z. Positron-Emission Tomography Imaging of the Angiotensin II Subtype 1 Receptor in Swine Renal Artery Stenosis. Hypertension 2008; 51:466-73. [DOI: 10.1161/hypertensionaha.107.102715] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The angiotensin II subtype 1 receptor (AT
1
R) has been linked to the development and progression of renovascular hypertension. In this study we applied a pig model of renovascular hypertension to investigate the AT
1
R in vivo with positron-emission tomography (PET) and in vitro with quantitative autoradiography. AT
1
R PET measurements were performed with the radioligand [
11
C]KR31173 in 11 control pigs and in 13 pigs with hemodynamically significant renal artery stenosis; 4 were treated with lisinopril for 2 weeks before PET imaging. The radioligand impulse response function was calculated by deconvolution analysis of the renal time-activity curves. Radioligand binding was quantified by the 80-minute retention of the impulse response function. Median values and interquartile ranges were used to illustrate group statistics. Radioligand retention was significantly increased (
P
=0.044) in hypoperfused kidneys of untreated (0.225; range: 0.150 to 0.373) and lisinopril-treated (0.237; range:0.224 to 0.272) animals compared with controls (0.142; range:0.096 to 0.156). Increased binding of [
11
C]KR31173 documented by PET in vivo was confirmed by in vitro autoradiography. Both in vivo and in vitro binding measurements showed that the effect of renal artery stenosis on the AT
1
R was not abolished by lisinopril treatment. These studies provide insight into kidney biology as the first in vivo/in vitro experimental evidence about AT
1
R regulation in response to reduced perfusion of the kidney. The findings support the concept of introducing AT
1
R PET as a diagnostic biomarker of renovascular disease.
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Affiliation(s)
- Jinsong Xia
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - Esen Seckin
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - Yan Xiang
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - Melin Vranesic
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - William B. Mathews
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - Kelvin Hong
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - David A. Bluemke
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - Lilach O. Lerman
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
| | - Zsolt Szabo
- From the Departments of Radiology (J.X., E.S., M.V., W.B.M., K.H., D.A.B., Z.S.) and Physiology (Y.X.), Johns Hopkins Medical Institutions, Baltimore, Md; Department of Medicine (L.O.L.), Mayo Clinic College of Medicine, Rochester, Minn
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Zober TG, Mathews WB, Seckin E, Yoo SE, Hilton J, Xia J, Sandberg K, Ravert HT, Dannals RF, Szabo Z. PET Imaging of the AT1 receptor with [11C]KR31173. Nucl Med Biol 2006; 33:5-13. [PMID: 16459253 PMCID: PMC1819586 DOI: 10.1016/j.nucmedbio.2005.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 08/22/2005] [Accepted: 08/23/2005] [Indexed: 10/25/2022]
Abstract
AIM The goal of this study was to investigate the binding characteristics of [(11)C]KR31173 and its applicability for PET studies of the AT(1) receptor (AT(1)R). METHODS Ex vivo biodistribution and pharmacology were tested in mice. PET imaging was performed in mice, beagle dogs and a baboon. To assess nonspecific binding, PET imaging was performed both before and after pretreatment with a potent AT(1)R antagonist. In the baboon, PET imaging was also performed with the previously developed radioligand [(11)C]L-159,884 for comparison. RESULTS Ex vivo biodistribution studies in mice showed specific binding rates of 80-90% in the adrenals, kidneys, lungs and heart. Specific binding was confirmed in mice using small animal PET. In dogs, renal cortex tissue concentration at 75-95 min postinjection (pi) was 63 nCi/ml per millicurie at a specific binding rate of 95%. In the baboon renal cortex, tissue activity at 55-75 min pi was 345 nCi/ml per millicurie. In the baboon the specific binding of [(11)C]KR31173 was higher (81%) than the specific binding of [(11)C]L-159,884 (34%). CONCLUSION [(11)C]KR31173 shows accumulation and significant specific binding to the AT(1)R in the kidneys of mice, dogs and baboon. These findings suggest that this radioligand is suited for imaging the renal cortical AT(1)R in multiple species.
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Affiliation(s)
- Tamas G. Zober
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - William B. Mathews
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - Esen Seckin
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - Sung E. Yoo
- The Center for Biological Modulators, The Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - John Hilton
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - Jinsong Xia
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - Kathryn Sandberg
- Department of Medicine, Georgetown University, Washington, DC U.S.A
| | - Hayden T. Ravert
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - Robert F. Dannals
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
| | - Zsolt Szabo
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD U.S.A
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Haufe SE, Riedmüller K, Haberkorn U. Nuclear medicine procedures for the diagnosis of acute and chronic renal failure. Nephron Clin Pract 2006; 103:c77-84. [PMID: 16543760 DOI: 10.1159/000091576] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The focus of this review is on the current role of nuclear imaging studies in the clinical evaluation of patients with acute and chronic renal failure. In this setting nuclear imaging has two roles: diagnostic and prognostic, indicating that these methods are an essential component in the evaluation of renal diseases. The functional assessment of the kidney by nuclear medicine procedures is based on the use of radioisotopes bound to non-metabolized molecules with known pharmacokinetics. Renal scintigraphy is usually applied for the assessment of renal function expressed as glomerular filtration rate, effective renal plasma flow or more generally kidney perfusion. Newer methods rely on positron emission tomography, which allows the generation of images with higher resolution and absolute quantitation of biological processes such as transport activities, enzyme activities or angiotensin receptors.
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Affiliation(s)
- Sabine E Haufe
- Department of Nuclear Medicine, University of Heidelberg, Heidelberg, Germany
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24
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Abstract
Positron emission tomography (PET) is perfectly suited for quantitative imaging of the kidneys, and the recent improvements in detector technology, computer hardware, and image processing software add to its appeal. Multiple positron emitting radioisotopes can be used for renal imaging. Some, including carbon-11, nitrogen-13, and oxygen-15, can be used at institutions with an on-site cyclotron. Other radioisotopes that may be even more useful in a clinical setting are those that either can be obtained from radionuclide generators (rubidium-82, copper-62) or have a sufficiently long half-life for transportation (fluorine-18). The clinical use of functional renal PET studies (blood flow, glomerular filtration rate) has been slow, in part because of the success of concurrent technologies, including single-photon emission computed tomography (SPECT) and planar gamma camera imaging. Renal blood flow studies can be performed with O-15-labeled water, N-13-labeled ammonia, rubidium-82, and copper-labeled PTSM. With these tracers, renal blood flow can be quantified using a modified microsphere kinetic model. Glomerular filtration can be imaged and quantified with gallium-68 EDTA or cobalt-55 EDTA. Measurements of renal blood flow with PET have potential applications in renovascular disease, in transplant rejection or acute tubular necrosis, in drug-induced nephropathies, ureteral obstruction, before and after revascularization, and before and after the placement of ureteral stents. The most important clinical application for imaging glomerular function with PET would be renovascular hypertension. Molecular imaging of the kidneys with PET is rather limited. At present, research is focused on the investigation of metabolism (acetate), membrane transporters (organic cation and anion transporters, pepT1 and pepT2, GLUT, SGLT), enzymes (ACE), and receptors (AT1R). Because many nephrological and urological disorders are initiated at the molecular and organelle levels and may remain localized at their origin for an extended period of time, new disease-specific molecular probes for PET studies of the kidneys need to be developed. Future applications of molecular renal imaging are likely to involve studies of tissue hypoxia and apoptosis in renovascular renal disease, renal cancer, and obstructive nephropathy, monitoring the molecular signatures of atherosclerotic plaques, measuring endothelial dysfunction and response to balloon revascularization and restenosis, molecular assessment of the nephrotoxic effects of cyclosporine, anticancer drugs, and radiation therapy. New radioligands will enhance the staging and follow-up of renal and prostate cancer. Methods will be developed for investigation of the kinetics of drug-delivery systems and delivery and deposition of prodrugs, reporter gene technology, delivery of gene therapy (nuclear and mitochondrial), assessment of the delivery of cellular, viral, and nonviral vectors (liposomes, polycations, fusion proteins, electroporation, hematopoietic stems cells). Of particular importance will be investigations of stem cell kinetics, including local presence, bloodborne migration, activation, seeding, and its role in renal remodeling (psychological, pathological, and therapy induced). Methods also could be established for investigating the role of receptors and oncoproteins in cellular proliferation, apoptosis, tubular atrophy, and interstitial fibrosis; monitoring ras gene targeting in kidney diseases, assessing cell therapy devices (bioartificial filters, renal tubule assist devices, and bioarticial kidneys), and targeting of signal transduction moleculas with growth factors and cytokines. These potential new approaches are, at best, in an experimental stage, and more research will be needed for their implementation.
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Affiliation(s)
- Zsolt Szabo
- Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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